The specific aim of this protocol is to test the following hypothesis: that black women, as compared to white women, have greater predisposing factors which contribute to the development of obesity. These factors are: a) lower energy expenditure and resting fat oxidation; b) a relative failure to appropriately increase fat oxidation in response to a high fat diet and to moderate exercise; c) a lower ratio of Type I(slow twitch, fat oxidizing) to Type II muscle fibers; d) a lower activity of muscle lipoprotein lipase (LPL); e) a higher activity of adipose tissue LPL.